A CDMA system has become a development direction of the third generation mobile communication because of its advantages such as high capacity, high service quality, and good confidentiality. In an actual CDMA communication system, certain correlation exists between user signals, so that multiple access interference (Multiple Access Interference) exists in the communication system. Multiple access interference generated by a single user is usually small; however, when the number of users is increased, for a certain user, the sum of multiple access interference generated by other users on the user is large. When a near-far effect exists and a signal amplitude of a certain user is large, multiple access interference generated by the user on a user having a weak signal is large. A single-user receiver cannot eliminate an impact of the multiple access interference on user signal detection, and the multiple access interference limits improvement of capacity and performance of the CDMA system.
A multi-user detection technology is a key technology for overcoming interference in the CDMA system and is an enhanced technology for improving the capacity of the CDMA system. The multi-user detection technology can make full use of information of multiple users and perform joint detection on multiple user signals, so as to lower an impact of the multiple access interference on receiver performance as much as possible and improve the capacity of the system.
An interference cancellation method is a multi-user detection technology, where a signal of an expected user is regarded as a useful signal and signals of other users are regarded as interference signals; first, interference of signals of other users is eliminated from a received signal to obtain the signal of the expected user, and then detection is performed on the signal of the expected user, so as to improve the performance of the system.
In an interference cancellation system, a canceled user and a benefited user are separately scheduled. The canceled user is first scheduled and processed, and after the cancellation is completed, the benefited user is scheduled and processed, so as to guarantee that the benefited user can enjoy a cancellation gain.
In the process of implementation of the foregoing scheduling, the inventor finds that the prior art at least has the following problem: When it is guaranteed that a benefited user enjoys a cancellation gain, if the number of canceled users is less than the number of benefited users, the system allocates a cancellation processing time the same as the number of benefited users to process the canceled users, so that the cancellation processing time is longer than time required to process the canceled user, and a processing delay of the benefited user is increased; therefore, data of a part of benefited users that needs to be processed is discarded because the processing delay exceeds timeout duration of the user, and the processing capability of the system is not fully used.